Experimental and numerical investigation on the performance of three-legged CFST latticed columns under lateral cyclic loadings

To evaluate the cyclic performance of composite latticed columns, experiments and numerical modelling of three-legged concrete filled steel tube (CFST) latticed columns under constant axial compressive force and lateral cyclic loadings were conducted. Experiments of eight specimens, including 6 CFST latticed columns and 2 steel latticed columns, were carried out with various axial compression ratio and diameter-to-thickness ratio of the tube section in the limb. The failure pattern, hysteretic behaviour, bearing capacity, initial stiffness and accumulated energy dissipation of the specimens were investigated. The experimental results reveal that, under cyclic loadings, CFST latticed columns have better performance than the corresponding steel latticed columns; however, three-legged CFST latticed specimens show different behaviour in two loading directions owing to the different capacity of the CFST members under tension and compression. A finite element analysis (FEA) model was developed to simulate the performance of three-legged CFST latticed columns under lateral cyclic loadings, and the feasibility of the FEA model was verified by the comparison against test results.